1. Field of the Invention
The present invention relates to a frame structure for a saddle riding type vehicle, i.e., a 4-wheel buggy which is suitable for running on ungraded land.
2. Description of Related Art
Japanese Published Patent Application No. Sho 63-1234 describes a frame structure for a 4-wheel buggy in which a body frame is constructed of a pair of right and left pipe frames that form a loop in side view. An engine which is loaded or unloaded from a side of the body is supported within the loop formed by the pipe frames. The front wheel is suspended and a steering shaft is supported by the front area of the frame structure, while a saddle riding type seat is supported on the upper part of the engine. The rear wheels are suspended by the rear part of the frame structure.
In the above-described frame structure, since the engine must be loaded or unloaded from a side of the body, many steps are required to load and unload the engine therefrom. Therefore, maintenance on the engine is increased. Moreover, the engine is not used as a strength member, which would increase the rigidity of frame, because the engine must be supported through vibration mounts to the body frame even though the engine is formed of a rigid member. Therefore, the total weight of the body frame increases. Furthermore, since the body frame is entirely assembled by welding, the number of welding points increases resulting in an increase of assembling steps and manufacturing cost.